This invention relates generally to the field of laser devices, and more specifically to improvements in heat exchangers for cooling and supporting high energy laser mirror surfaces.
The requirements of acceptable performance placed on a high energy laser mirror in the high power density environment to which it is subjected during laser operation dictates that the mirror be configured, and be constructed of materials, to be thermally stable. Heat deposited into the mirror structure by the laser must be conducted away from the mirror surfaces to avoid damage to the temperature sensitive coatings which often conventionally comprise the optical surface to enhance reflectivity. The heat exchanger and other substructure supporting the high energy laser surface must exhibit the desired heat transfer characteristics and at the same time maintain structural integrity and resistance to thermal effects for the laser mirror to function properly over an acceptably long operational lifetime.
The present invention provides a novel laser mirror and heat exchanger/substructure configuration together with the process for fabricating same. In a representative embodiment described herein, a carbon/carbon fiber matrix material is selected for the supporting substrate structure since this material may be contoured to a variety of complex shapes, exhibits the desirable thermal properties to withstand the high power density environment characteristically associated with high power laser operation, and exhibits thermal and other physical properties rendering it highly desirable as a compatible substrate material to support a heat exchanger structure of tungsten/tungsten carbide. The tungsten/tungsten carbide heat exchanger may be deposited onto the substrate by vapor deposition in the desired configuration, and a laser mirror surface may be polished into the surface of the heat exchanger. The novel structure of the present invention is lightweight and reparable, is highly creep resistant, has no machined slots or surfaces where concentrated stresses during thermal loading may arise, and may be joined in segments to provide laser mirrors of large (up to several meters) diameter. The heat exchanger also exhibits superior corrosion resistance.
It is therefore an object of the present invention to provide an improved high energy laser mirror and heat exchanger.
It is a further object of the present invention to provide an improved high energy laser mirror and heat exchanger that is lightweight, reparable and nondeforming under the thermal and mechanical loads resulting from system operation.
It is yet another object of the present invention to provide a process for fabricating an improved laser mirror and heat exchanger.
These and other objects of the present invention will become apparent as the detailed description of certain embodiments thereof proceeds.